Convert DIN-9pin (6channel) to 3xTRS 3.5mm | Noob help!

[Nexovus]

I'm not sure where I should have posted this, im a noob with this kind of thing. I would greatly appreciate any help, suggestions, ideas or being pointed in the right direction!

I was given a Sanyo DWM-3500, an older 5.1 surround sound system with a powered sub and a main unit. (I know its not good, but its better than what I have and right now I cant spend money.) I would like to connect my computer to it. The problem is that I am missing the main unit which the sub connects to via a DIN-9pin. Im not sure if its proprietary or if it follows a template/standard, but I want to connect it to 3x TRS 3.5 mm outputs from my computer. How can I determine what each of the pins in the DIN-9 are for, and then how can use that information to figure out how to convert the the 6 channels being output from my computer and what the other 3 are for (just guessing thats how it will work).

My computer's output:


A diagram of the sound system with a few notes:


Specs:
Powered Subwoofer (ASX-3500)
Continuous minimum sine wave RMS power output
into 6 ohms at 70 Hz with no more than 10 % total harmonic
distortion (with the other amplifiers off) ................. 75 Watts
Satellite Speakers (Front Left & Right, Center, Surround Left & Right)
Continuous minimum sine wave RMS power output per
channel into 8 ohms at 1 kHz with no more than 10 %
total harmonic distortion (with the other amplifiers off)
.................................................. .................................25 Watts
AUDIO INPUT (6-CHANNEL):
DIN 9-pin
SPEAKERS (Output):
FRONT (L/R): 8 Ω
CENTER: 8 Ω
SURROUND (L/R): 8 Ω
Power requirements:
AC 120V, 60 Hz
Power consumption:
150 Watts
Unit used:
6.5" (16 cm) diameter, Cone type

Satellite Speaker
Front left, Front right, Center, Surround left, and Surround right speakers
(SX-TS3000S, magnetic shield)
Unit used:
3.1" (8 cm) diameter, Cone type, Full range
Maximum music power handling capacity:
50 Watts
Nominal impedance:
8 Ω

I dont want to replace the main unit, I want to bypass it. Sanyo customer support is HORRIBLE too . I would greatly appreciate any / all help! Im pretty handy and I follow directions well too.

[Nexovus]

Does anyone have any suggestions or ideas on what I can do at all?

[SoNic_real_one]

Open the sub and follow the conductors. Post pics here eventually.

[Nexovus]

Here is a gallery of the pictures I took..
ImageShack Album - 13 images
I couldnt get the camera to focus so I recreated the PCB board in photoshop..

Top:


Bottom:


The In wires:

[SoNic_real_one]

Solder on the back of the board six pairs of wires (one signal+ground for each channel) to six RCA female jacks (three pairs). Drill holes for the jacks in the back of the case. One pair will be: Front Left - Front Right, the second S/L - S/R, the third Sub - Center. The 9 pin connector remains disconnected.
The two dots that you left unmarked are the "Mute/Stand By" - probably if you short them you will mute the amp.

Or if you don't plan to use the 9 pin DIN connector ever, just cut the small white connectors and solder them on the female RCA.
From your computer you have the standard 3.5mm stereo jack- red/white RCA cable - three of them. The "surround back" channels (jack) will not be used.

[Nexovus]

Thank you so much! I had thought of that, but I had no idea if that would work or if it would mess something up. I plan on never using the DIN connector again, so I will solder the wires directly to the RCA ports. I will look up a tutorial on how to do that since im not familiar with it, ive always been a software guy :P If you happen to know of one lemme know! Once again, thank you!